Concept 22
DNA words are three letters long.

Marshall Nirenberg, Har Gobind Khorana, and Robert Holley shared the 1968 Nobel Prize for Physiology and Medicine. Nirenberg and Khorana cracked the genetic code. Holley sequenced and deduced the structure of the first tRNA molecule.

Har Gobind Khorana (1922-2011)

Har Khorana was born in Raipur, West Pakistan. His father was a clerk in the British Indian government. Although the family was not well-to-do, Khorana's father made sure that his children had an education.

Khorana went to Punjab University in Lahore and graduated with a Master of Science. In 1945, a fellowship from the government of India gave him the opportunity to study abroad. He went to the University of Liverpool where he obtained his doctorate.

In 1952, Khorana was offered a job at the University of British Columbia where he was able to work fairly independently on various research projects involving phosphate esters and nucleic acids. The work on the chemical synthesis of ribotrinucleotides for protein synthesis was initiated at this time.

From 1970 until his retirement in 2007, Khorana was the Alfred P. Sloan Professor of Biology and Chemistry at the Massachusetts Institute of Technology. The Khorana Program was founded in his honor in 2007 by the University of Wisconsin-Madison, the Government of India, and the Indo-US Science and Technology Forum, with the mission to build a community of scientists, industrialists, and social entrepreneurs in the United States and India.

Modern methods used to synthesize oligonucleotide PCR primers are still based on the principles of Khorana's method to make defined sequences of DNA for his experiments.

Why is redundancy built into the genetic code? Why not just have the "extra" codons not code for anything at all?